Tony La Russa can trace his relationship with Dave Stewart all the way back to the very first game he managed for the Oakland Athletics, when he pulled the recently acquired right-handed reliever out of the bullpen to start against Roger Clemens in the summer of 1986.

Stewart beat Clemens and went on win three World Series while becoming “like a brother from another mother,” according to La Russa.

Along the way, the Hall-of-Fame manager learned of a hidden talent that Stewart only revealed when the clubhouse doors closed, or maybe after a couple drinks at dinner. He has kept the secret closely guarded for nearly 40 years. Until now.

You could say “Smoke” has pipes. That’s right: Stewart can sing.

“We’ve always kidded that when he gets excited, he sounds like the Bee Gees,” La Russa said of Stewart, now 68, who is better known for his imposing stare and impressive fastball that led him to a no-hitter and a World Series MVP. “I’m confident that he’s got — what’s the word? He’s got good range.”

Stewart will show off that range publicly for the first time next Saturday with a band that includes members of Santana, the Who, Huey Lewis and the News, and the Doobie Brothers, unveiling his vocal stylings at the Lesher Center for the Arts in Walnut Creek for La Russa’s annual fundraiser to support his nonprofit for animal welfare.

La Russa can remember “many, many times, if we were at a social event and there was music, he’d be next to me and I could hear him singing the lyrics from the songs, especially if they were Motown.” His debut performance will lean more soft and soulful: Two songs by Chris Stapleton and one Bill Withers number.

A longtime East Bay resident, La Russa has put on the fundraiser for years, often involving Stewart in one way or another. He had stepped on the mound for La Russa so many times, but never had Stewart stepped on stage with a band, in front of an audience.

Like many good stories, it began with a pair of old friends on a golf course.

La Russa and Stewart don’t hit the links often, but they found themselves in a foursome in the Phoenix area one day last spring. La Russa, now 81 and fully recovered from cancer treatment, was entering his third season as a senior advisor for the White Sox, while Stewart was working for the A’s.

“We made a bet, and there were some consequences for whoever lost,” La Russa said. “If Stew lost, he was going to have to sing at this event. I actually told him in October, I said, ‘Look man, I’m not going to ruin our friendship over a stupid bet. You don’t have to do it.’ And he said, ‘I’m singing.’”

Commendable as Stewart’s insistence is to hold up his end of the bargain, the punishment is far more preferable — and probable to pull off — than what La Russa hypothetically would have had to endure.

“At the next A’s-White Sox game, I would have had to kiss his (expletive) at home plate before the first pitch,” La Russa said. “I would have found a way to avoid that. Stew is more honorable than I am.”

Dusty Baker, Jose Canseco and Dennis Eckersley are expected to attend the event, which also includes performances by Tony Lindsay of Santana and “Phantom of the Opera” singer Franc D’Ambrosio, as well as a panel discussion looking back on big moments from the careers of Stewart and others.

Walter Haas, the former A’s president, purchased a group of tickets so that some former club employees could attend, La Russa said.

“It’s going to be a kind of reunion,” said La Russa, whose career in baseball now spans seven decades. Debuting at 18 years old for the Kansas City Athletics, his relationship with the franchise dates back even further than its tie to Oakland. He was there when the A’s arrived at the Coliseum in 1968 and spent parts of five seasons as a part-time middle infielder. He returned to manage in 1986 and led the “Bash Brothers” era A’s to three straight American League pennants.

That history occurred in Oakland. The A’s play in West Sacramento now, en route to Las Vegas.

“We always felt like the success of the franchise and the support of the fans was as good as any place, so there’s a disappointment” in the A’s leaving Oakland,” La Russa said. “There was all that talk about going to San Jose. I wish that had happened. We always thought that if Oakland didn’t work we could move to Pleasanton or Livermore, just because the fan base is so strong. Now it’s Las Vegas, and I can’t say that we’re not disappointed. But we’re still with the A’s wherever they go.”

Heart problems forced La Russa to retire from his 35-year managerial career midway through 2022, and he began undergoing treatment for cancer shortly thereafter. He had surgery in January 2023 and that spring began his new advisory role with the White Sox. That summer, he attended the Hall of Fame ceremony in Cooperstown, “and I remember, I saw pictures of me and thought, ‘I should’ve stayed home.’ …

“That first year was (difficult),” La Russa said. “But I’m feeling better.”

Less than a month after the fundraiser, pitchers and catchers will report to Arizona for spring training. So will La Russa. He plans to be in camp with the White Sox in the first part of February. Recently, he exchanged texts with Joe Torre, who now works in the league office, about the upcoming labor negotiations.

“It’s been my life forever,” La Russa said. “It’s the only thing I know how to do, so it’s fortunate I’ve been able to stay connected to (the game).”